Oyster mushroom functions as an anti-hyperglycaemic through phosphorylation of AMPK and increased expression of GLUT4 in type 2 diabetic model rats

Objectives: Traditionally, mushrooms have been used to reduce hyperglycaemia. However, the mechanism underlying this effect has not yet been explored. AMP-activated protein kinase (AMPK) is known to reduce hyperglycaemia through an insulin-independent pathway. This study aimed to observe the effect of oyster mushroom powder (OMP) on phosphorylation of AMPK (p-AMPK) and expression of GLUT4 mRNA in diabetic model rats. Methods: Long-Evans rats were used to develop type 2 diabetic model rats through intraperitoneal induction of streptozotocin (STZ). OMP was supplemented at 5% with the usual feed of rats for 8 consecutive weeks. Then, the rats were sacrificed. RNA was extracted by the TRIzol reagent, and proteins were extracted from different tissues with RIPA lysis buffer. Expression of GLUT4 mRNA was measured through cDNA-PCR techniques, and p-AMPK was detected using western blotting. The band intensities of the PCR products and proteins were measured using Image J software. Results: Supplementation of OMP for 8 weeks resulted in a reduction of the serum glucose level in STZ-induced, type 2 diabetic model rats. The levels of p-AMPK, as a ratio relative to fl-actin, increased in the muscle and adipose tissues of mushroom-treated type 2 diabetic model rats, compared to those in control diabetic model rats. Expression of GLUT4, as a ratio relative to GAPDH, increased significantly in both the muscle and adipose tissues of mushroom-treated diabetic rats. Conclusion: Oyster mushroom may decrease hyperglycaemia through increased p-AMPK and also expression of GLUT4 in the muscle and adipose tissues.